What is the name of Mario's brother?

Mario's brother is Luigi, his younger fraternal twin and one of the most recognizable characters in Nintendo history. Luigi was introduced in Mario Bros. in 1983 as the second player's character, giving Mario's arcade adventures a cooperative partner.

Early Luigi closely resembled Mario, differing mainly through his green clothing. Over time, Nintendo developed a distinct personality and play style for him: Luigi is generally taller and slimmer, and in many games he jumps higher while handling less precisely. His nervous, ghost-fearing persona became especially prominent in Luigi's Mansion, released for the Nintendo GameCube in 2001.

Luigi is not Mario's son, cousin, or rival. Wario is Mario's self-described arch-rival, while Yoshi is a dinosaur companion and Toad is a trusted Mushroom Kingdom ally. Those characters are frequent answer choices because they are closely associated with Mario.

Luigi has also starred in his own games, including Luigi's Mansion and Luigi's Mansion: Dark Moon, and co-led the Mario & Luigi role-playing series. His green cap and clothing deliberately contrast with Mario's red design, making the brothers easy to distinguish.